5 gallon can of Protectosil Chem-Trete 40 VOC. This is a clear, penetrating, breathable water repellent for use on exterior above-grade concrete, brick masonry, concrete masonry units and some natural stones. The product penetrates the surface and bonds chemically to the substrate, resulting in permanent attachment of the water repellent molecule. It is not a coating and as a result will not discolor or change the surface appearance in anyway.
Buying this online will cost $400-$500!!! Simply apply with a pump sprayer or brush on. Extra from a project. Been sitting in my garage a couple years.